This is the third OLYMPIADS IN INFORMATICS conference organized during the IOI Plovdiv, Bulgaria.

In this year, when IOI celebrates its 20 years anniversary, we should think back over the years. Think of the thousands of students who have been given the wonderful opportunity of attending an IOI, and of the hundreds of thousands (if not more) who have been touched across the world by national endeavours. The national olympiads do not exist in isolation, and the papers being presented in the conference show how similar problems arise in different environments. Papers of this conference concentrate on task development and grading.